furrykef wrote:It doesn't really surprise me that I could hear 'em all. A while back we had this TV, and occasionally my stepfather or mother would accidentally turn off the cable box instead of the TV (the same button on the remote controls both). Since this resulted in a blank screen, they couldn't tell the difference. But I could always hear when it happened because it made a faint, high-pitched sound. (The screen also glowed a bit -- it wasn't pure black -- but I could still tell very easily without even looking at the screen.)

I think that is the 19kHz pilot frequency for the audio signal that you were hearing. I used to be able to hear that as well when I was in elementary school. One can tell if whether the TV set is on or off without any signal/image.

cell phones (with young kids) have been using these high tone ringers for a bit now. The kids can hear it ring but the older folks can't. So, you can put a high tone ringer on and get away with the phone ringing in class, unless your teacher has good ears and busts you for it.

My daughter tried this a few times at home, thinking I couldn't hear them. When I told her to answer her phone a few times when I heard the sounds, she decided it wasn't so sneaky anymore.

becki_kanou wrote: I could just barely hear it. Not enough to drive me away from the public parks at midnight though!

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Sairana wrote:

astaroth wrote:
I tried this link at home and it was so annoying the sound I had to cover my ears and flee the premises with terror in my eyes ... ok not quite that bad But it was an annoying sound which made me think of what could happen if I quietly sleeping at night and the cops would turn on that device for a couple of teenagers ... I think I wouldn't be very much happy about it.

I'm in a coffee place now, age raging from 20+ all the way over 50 and tried the link again. No one frown (except me ... ) but I don't know if it says more about the sound than about the ability of mind-one's-own-business

I have to wonder how many of those people are going to their next physical and mention to their doctor, "And one day I was having coffee, and my ears started ringing REALLY LOUDLY...."

This reminded me of "Mars Attack!". I thought the mosquito tone might have been to teenagers what a country song is to a Martian in "Mars Attack!". But after reading Two_heads-san's post, there seems to be several ways of using high-frequency tones.

Mystique wrote:

furrykef wrote:It doesn't really surprise me that I could hear 'em all. A while back we had this TV, and occasionally my stepfather or mother would accidentally turn off the cable box instead of the TV (the same button on the remote controls both). Since this resulted in a blank screen, they couldn't tell the difference. But I could always hear when it happened because it made a faint, high-pitched sound. (The screen also glowed a bit -- it wasn't pure black -- but I could still tell very easily without even looking at the screen.)

I think that is the 19kHz pilot frequency for the audio signal that you were hearing. I used to be able to hear that as well when I was in elementary school. One can tell if whether the TV set is on or off without any signal/image.

When I was in Japan last summer, I noticed that anytime I walked near an adult club in Tokyo, I always heard a really high-pitched sound such as this. The first time it happened, I thought it was just some quirk with the light-up sign next to the entrance, but it kept happening. I wonder if club owners utilize this, or if it was just some weird coincidence.

two_heads_talking wrote:on the other hand, elephants kick out low droaning noises in the 20-100 hz range that you feel, rather than hear.. lol

It's actually just roughly the 0-40 Hz or so range that you feel rather than hear. In fact, depending on your hearing, you can hear down to about 20 Hz. I can hear a 20 Hz tone sine wave, but I have to turn the volume way up. (Note that speakers may attenuate such low frequencies, so this may or may not be caused by my speakers... I imagine it is quite hard to hear such frequencies, though.) It sounds more like flapping, though... less than 20 Hz and it's pretty much all flapping.

I can hear a 40 Hz tone without turning up my volume so much, and 60 Hz comes through loud and clear at normal volume. Funnily enough, my subwoofer resonates quite heavily if I turn up the volume, though.

Txkun wrote:I can clearly hear the Teenager sound test (I'm 31 years old) and it's very annoying!
Woulnd't be nicer for our poor easrs (and animal's ears too) just to teach young people how to behave?

This is not a frequency that bothers animals at all. Where did you get the information that it bothered animals?

Well it a supposition since I know there are whistles that can be heard only by dogs.
I can't hear them so I think their frequency is higher that this Teenager sound. For this reason I think an animal can hear this sound. It could be that they aren't bothered as much as I do but I think no one would like to ear a whistle going on all night long. Anyway even if animals ears don't hurt mine do.

p.s. ah just read about the 19k thing. Interesting! Now I wonder if birds ear the same as dogs & cats or like humans. Time to google

two_heads_talking wrote:on the other hand, elephants kick out low droaning noises in the 20-100 hz range that you feel, rather than hear.. lol

It's actually just roughly the 0-40 Hz or so range that you feel rather than hear. In fact, depending on your hearing, you can hear down to about 20 Hz. I can hear a 20 Hz tone sine wave, but I have to turn the volume way up. (Note that speakers may attenuate such low frequencies, so this may or may not be caused by my speakers... I imagine it is quite hard to hear such frequencies, though.) It sounds more like flapping, though... less than 20 Hz and it's pretty much all flapping.

I can hear a 40 Hz tone without turning up my volume so much, and 60 Hz comes through loud and clear at normal volume. Funnily enough, my subwoofer resonates quite heavily if I turn up the volume, though.

- Kef

Hmm, I was always told that up to 100hz you could feel the vibrations (assuming all things equal in volume of course). I'm aware that people can hear as low as 20hz, but it's usually mixed in with so many other freqs, that you feel it rather than actually hearing it.

Some friends and I did a complete freq track song, where we manipulated freqs rather than 'sounds' and it was interesting to see who could hear what parts.. Some of our friends even figured out there was a beat/bass track within the freqs.. But that was alsmost 2 decades ago.

two_heads_talking wrote:Hmm, I was always told that up to 100hz you could feel the vibrations (assuming all things equal in volume of course). I'm aware that people can hear as low as 20hz, but it's usually mixed in with so many other freqs, that you feel it rather than actually hearing it.

Yeah, that may well be true, though it depends. If a 60 Hz tone is very dissonant with a piece of music, it'd probably stick out. But if it's not dissonant, you might not hear it at all.